| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * This file contains vfs directory ops for the 9P2000 protocol. |
| 4 | * |
| 5 | * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> |
| 6 | * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/errno.h> |
| 11 | #include <linux/fs.h> |
| 12 | #include <linux/file.h> |
| 13 | #include <linux/stat.h> |
| 14 | #include <linux/string.h> |
| 15 | #include <linux/sched.h> |
| 16 | #include <linux/slab.h> |
| 17 | #include <linux/uio.h> |
| 18 | #include <linux/fscache.h> |
| 19 | #include <net/9p/9p.h> |
| 20 | #include <net/9p/client.h> |
| 21 | |
| 22 | #include "v9fs.h" |
| 23 | #include "v9fs_vfs.h" |
| 24 | #include "fid.h" |
| 25 | |
| 26 | /** |
| 27 | * struct p9_rdir - readdir accounting |
| 28 | * @head: start offset of current dirread buffer |
| 29 | * @tail: end offset of current dirread buffer |
| 30 | * @buf: dirread buffer |
| 31 | * |
| 32 | * private structure for keeping track of readdir |
| 33 | * allocated on demand |
| 34 | */ |
| 35 | |
| 36 | struct p9_rdir { |
| 37 | int head; |
| 38 | int tail; |
| 39 | uint8_t buf[]; |
| 40 | }; |
| 41 | |
| 42 | /** |
| 43 | * dt_type - return file type |
| 44 | * @mistat: mistat structure |
| 45 | * |
| 46 | */ |
| 47 | |
| 48 | static inline int dt_type(struct p9_wstat *mistat) |
| 49 | { |
| 50 | unsigned long perm = mistat->mode; |
| 51 | int rettype = DT_REG; |
| 52 | |
| 53 | if (perm & P9_DMDIR) |
| 54 | rettype = DT_DIR; |
| 55 | if (perm & P9_DMSYMLINK) |
| 56 | rettype = DT_LNK; |
| 57 | |
| 58 | return rettype; |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir |
| 63 | * @filp: opened file structure |
| 64 | * @buflen: Length in bytes of buffer to allocate |
| 65 | * |
| 66 | */ |
| 67 | |
| 68 | static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen) |
| 69 | { |
| 70 | struct p9_fid *fid = filp->private_data; |
| 71 | |
| 72 | if (!fid->rdir) |
| 73 | fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL); |
| 74 | return fid->rdir; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * v9fs_dir_readdir - iterate through a directory |
| 79 | * @file: opened file structure |
| 80 | * @ctx: actor we feed the entries to |
| 81 | * |
| 82 | */ |
| 83 | |
| 84 | static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx) |
| 85 | { |
| 86 | bool over; |
| 87 | struct p9_wstat st; |
| 88 | int err = 0; |
| 89 | struct p9_fid *fid; |
| 90 | int buflen; |
| 91 | struct p9_rdir *rdir; |
| 92 | struct kvec kvec; |
| 93 | |
| 94 | p9_debug(P9_DEBUG_VFS, "name %pD\n", file); |
| 95 | fid = file->private_data; |
| 96 | |
| 97 | buflen = fid->clnt->msize - P9_IOHDRSZ; |
| 98 | |
| 99 | rdir = v9fs_alloc_rdir_buf(file, buflen); |
| 100 | if (!rdir) |
| 101 | return -ENOMEM; |
| 102 | kvec.iov_base = rdir->buf; |
| 103 | kvec.iov_len = buflen; |
| 104 | |
| 105 | while (1) { |
| 106 | if (rdir->tail == rdir->head) { |
| 107 | struct iov_iter to; |
| 108 | int n; |
| 109 | |
| 110 | iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen); |
| 111 | n = p9_client_read(file->private_data, ctx->pos, &to, |
| 112 | &err); |
| 113 | if (err) |
| 114 | return err; |
| 115 | if (n == 0) |
| 116 | return 0; |
| 117 | |
| 118 | rdir->head = 0; |
| 119 | rdir->tail = n; |
| 120 | } |
| 121 | while (rdir->head < rdir->tail) { |
| 122 | err = p9stat_read(fid->clnt, rdir->buf + rdir->head, |
| 123 | rdir->tail - rdir->head, &st); |
| 124 | if (err <= 0) { |
| 125 | p9_debug(P9_DEBUG_VFS, "returned %d\n", err); |
| 126 | return -EIO; |
| 127 | } |
| 128 | |
| 129 | over = !dir_emit(ctx, st.name, strlen(st.name), |
| 130 | v9fs_qid2ino(&st.qid), dt_type(&st)); |
| 131 | p9stat_free(&st); |
| 132 | if (over) |
| 133 | return 0; |
| 134 | |
| 135 | rdir->head += err; |
| 136 | ctx->pos += err; |
| 137 | } |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * v9fs_dir_readdir_dotl - iterate through a directory |
| 143 | * @file: opened file structure |
| 144 | * @ctx: actor we feed the entries to |
| 145 | * |
| 146 | */ |
| 147 | static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) |
| 148 | { |
| 149 | int err = 0; |
| 150 | struct p9_fid *fid; |
| 151 | int buflen; |
| 152 | struct p9_rdir *rdir; |
| 153 | struct p9_dirent curdirent; |
| 154 | |
| 155 | p9_debug(P9_DEBUG_VFS, "name %pD\n", file); |
| 156 | fid = file->private_data; |
| 157 | |
| 158 | buflen = fid->clnt->msize - P9_READDIRHDRSZ; |
| 159 | |
| 160 | rdir = v9fs_alloc_rdir_buf(file, buflen); |
| 161 | if (!rdir) |
| 162 | return -ENOMEM; |
| 163 | |
| 164 | while (1) { |
| 165 | if (rdir->tail == rdir->head) { |
| 166 | err = p9_client_readdir(fid, rdir->buf, buflen, |
| 167 | ctx->pos); |
| 168 | if (err <= 0) |
| 169 | return err; |
| 170 | |
| 171 | rdir->head = 0; |
| 172 | rdir->tail = err; |
| 173 | } |
| 174 | |
| 175 | while (rdir->head < rdir->tail) { |
| 176 | |
| 177 | err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, |
| 178 | rdir->tail - rdir->head, |
| 179 | &curdirent); |
| 180 | if (err < 0) { |
| 181 | p9_debug(P9_DEBUG_VFS, "returned %d\n", err); |
| 182 | return -EIO; |
| 183 | } |
| 184 | |
| 185 | if (!dir_emit(ctx, curdirent.d_name, |
| 186 | strlen(curdirent.d_name), |
| 187 | v9fs_qid2ino(&curdirent.qid), |
| 188 | curdirent.d_type)) |
| 189 | return 0; |
| 190 | |
| 191 | ctx->pos = curdirent.d_off; |
| 192 | rdir->head += err; |
| 193 | } |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | |
| 198 | /** |
| 199 | * v9fs_dir_release - close a directory or a file |
| 200 | * @inode: inode of the directory or file |
| 201 | * @filp: file pointer to a directory or file |
| 202 | * |
| 203 | */ |
| 204 | |
| 205 | int v9fs_dir_release(struct inode *inode, struct file *filp) |
| 206 | { |
| 207 | struct v9fs_inode *v9inode = V9FS_I(inode); |
| 208 | struct p9_fid *fid; |
| 209 | __le32 version; |
| 210 | loff_t i_size; |
| 211 | int retval = 0, put_err; |
| 212 | |
| 213 | fid = filp->private_data; |
| 214 | p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", |
| 215 | inode, filp, fid ? fid->fid : -1); |
| 216 | |
| 217 | if (fid) { |
| 218 | if ((S_ISREG(inode->i_mode)) && (filp->f_mode & FMODE_WRITE)) |
| 219 | retval = filemap_fdatawrite(inode->i_mapping); |
| 220 | |
| 221 | spin_lock(&inode->i_lock); |
| 222 | hlist_del(&fid->ilist); |
| 223 | spin_unlock(&inode->i_lock); |
| 224 | put_err = p9_fid_put(fid); |
| 225 | retval = retval < 0 ? retval : put_err; |
| 226 | } |
| 227 | |
| 228 | if ((filp->f_mode & FMODE_WRITE)) { |
| 229 | version = cpu_to_le32(v9inode->qid.version); |
| 230 | i_size = i_size_read(inode); |
| 231 | fscache_unuse_cookie(v9fs_inode_cookie(v9inode), |
| 232 | &version, &i_size); |
| 233 | } else { |
| 234 | fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL); |
| 235 | } |
| 236 | return retval; |
| 237 | } |
| 238 | |
| 239 | const struct file_operations v9fs_dir_operations = { |
| 240 | .read = generic_read_dir, |
| 241 | .llseek = generic_file_llseek, |
| 242 | .iterate_shared = v9fs_dir_readdir, |
| 243 | .open = v9fs_file_open, |
| 244 | .release = v9fs_dir_release, |
| 245 | }; |
| 246 | |
| 247 | const struct file_operations v9fs_dir_operations_dotl = { |
| 248 | .read = generic_read_dir, |
| 249 | .llseek = generic_file_llseek, |
| 250 | .iterate_shared = v9fs_dir_readdir_dotl, |
| 251 | .open = v9fs_file_open, |
| 252 | .release = v9fs_dir_release, |
| 253 | .fsync = v9fs_file_fsync_dotl, |
| 254 | }; |